Air compressor and the like



P 26, 9 A. COLEMAN 2,174,032

AIR COMPRESSOR AND THE LIKE Fil ed March 9, 1958 3 Sheets-Sheet 1INVENTOR v ALBERT l7. (5LEMA/l/ Sept.26, 1939. A. H. COLEMAN 2,174,032

AIR cbMPREsscR AND THE LIKE Filed March 9, 1938 3 Sheets-Sheet 2 l 4- i;II: I\

INVENTOR ALBERT bf GLEMA BY P 1939- A. H. COLEMAN 2,174,032

I AIR COMPRESSOR AND THE LIKE Filed March 9, 1938 3 Sheets- Sheet a AORNEYS Patented Sept. 26, 1939 UNITED STATES PATENT OFFICE AIRCOMPRESSOR AND THE LIKE Albert H. Coleman,

one-half to James Orlando, Fla., assignor of M. Campbell, Orlando, Fla.

Application March 9, 1938, Serial No. 194,894

4 Claims.

One of the objects of my invention is to provide a type of constructionthat shall produce a flow of. compressed air of such substantiallyuniform pressure that a storage tank shall not be needed.

Another object is to arrange the cylinders in such a Way as to promoteefiective cooling of the cylinders and air passages.

Another object is to produce an elficient, compact type of constructionthat lends itself to the manufacture of small portable air compressorsand vacuum pumps.

A further object is to provide efficient lubrication that shall requireno attention over long periods of time.

on line 2-2 of Fig. 3,

Fig. 3 is a sectional view taken substantially on line 3-3 of Fig. 2;and

Fig. 4 is a transverse sectional View through the head of one of thecylinders.

The cylinders and operating parts are carried by a casing formed in twoindicated at l2 and I3. Part lindrical portion main parts generally l2comprises a cyl4, one end of which is closed,

except for an opening l5 for the passage of the shaft structure laterdescribed. An annular plate l6 forms a closure for the open end ofportion I4 Plate I6 is secured in providing a chamber ll. place bymachine screws l8 Extending radially outwardly from the end of portionl4 adjacent the closure plate 15 are a plurality of box-like projectingportions [9, open at one side, which form the supports for thecompressor cylinders 20. The cylinders are all in the same plane. Part i3 of the casing comprises a plate portion 2! formed to closethe opensides of portions l9 and provided with a cylindrical portion 22, theouter end of which is closed by an annular plate 23 to form a chamber24.

Chamber l1 serves as the air intake chamber and is connected to theheads of the several cylinders 23, by pipes 25. As

shown in Fig. 4 the connection of pipes 25 to the interior of thecylinders is made through ball check valves 26.

through ball check valves 2 Air is supplied to chamber I I and permittedegress from chamber 24 through tubular bear-' ings, generally indicatedat 30, secured to the casing and by which the latter is rotatablymounted on shaft I I. Bearings 30 are identical 5 in construction, theparts being designated by the same reference characters so that adescrip tion of the inlet bearing serves to describe both.

The bearings 30 each comprise concentric spaced tubular members 3| and32 held in spaced relation by spacing collars 33 positioned at the endsof the tubular members, and rotatably mounted on shaft II on bearingbushings 34. Tubular member 3| is provided with a plurality of openings35, communicating with the annular l space 35a between members 3| and32, positioned outwardly of the casing, and with a plurality of openings36 leading from said space to the adjacent chamber of the casing. Air issupplied to chamber ll through a pipe 3'! connected to a stationarycollar 38 provided on its inner surface with a groove 39 into which pipe31 opens. Groove 39 communicates with openings 35 leading to chamber l1.

Egress from compression chamber 24 is provided through a pipe 40connected to the stationary collar 38 at the opposite end of the shaft.

The collars 38 are held against the ends of the rotatable casing l2'-l3by spring washers 4| and nuts 42, and are held against rotation by thepipes 31 and 40.

Each cylinder 20 is provided with a piston 45 connected by links 46 tothe outer end of operating lever. arms 41. The arms 41 are pivoted,intermediate their ends as at 48, to bosses 49 formed on the inner facesof casing portions l9, and the inner ends of the levers are providedwith cam rolls 50' riding in the grooves 5| of a cam 52 eccentricallyfixed on shaft I I. As shown, cam 52 is built up of a plurality ofplates held together by screws 53 and secured to shaft H by a set screw54, but any suitable cam construction may be used.

The casing and the parts carried thereby are adapted to be rotated inthe direction of the arrows in Figs. 1 and 2 by a pulley 55, secured tothe casing portion M by screws 56, and driven by a belt 5! from a motornot shown.

As best shown in Figs. 1 and 2,-the cylinders 20 are secured to thecasing at their bases by bolts 59, at an angle of substantially 90 tothe radius of the casing, that is, tangentially to their path of rotarymovement, and are exposed to the air on all sides. The heads of thecylinders are curved to direct the, air with substantial uni- 55 thepipe 31, annular groove formity around all sides of the cylinders andthe heads and sides are provided with cooling fins 60.

By this arrangement a very efficient cooling of the cylinders isobtained.

Referring to Figs. 2 and 3, it will be seen that the space between thetwo casing-sections l2 and I3 (note the space between the walls l9 and2! in Fig. 3) forms a closed chamber 6| that communicates with the inneror open ends of the cylinders and contains the cam 52 and all the movingparts, i. e., the rolls 50, the levers 41, the links 46 and the pistons45. This sealed chamber contains a suitable quantity of oil which in theoperation of the machine is thrown into contact with all the movingparts and keeps them properly lubricated. By reason of the tangentialarrangement of the cylinders, the tendency of centrifugal force to forcethe oil past the pistons into the head ends of the cylinders iscounteracted.

In operation, as the casing is rotated the cam rolls 5|] travel in thegrooves 5| .of the stationary eccentric cam, imparting a rocking motionto the arms 4'! which in turn reciprocate the pistons in the cylinders,the position of. the pistons at vari-= ous points in the rotation of thecasing being shown in Fig. 2. As the pistons are drawn rearwardly in thecylinders air is drawnin through 39, ports 35, annular space ports 36,chamber l1, pipes 25 and check valves 26 into the cylinders; and on theoutward movement the air is forced out through check valves 28, pipes21, chamber 24, ports 36, annular space 35 ports 35, annular groove 39to the discharge pipe 40.

As will be understood from Fig. 2, the inner wall of the cam grooves 5|,acting on the rolls 50, force the pistons inwardly, the outer walls ofsaid grooves producing the compression stroke.

The construction herein disclosed makes possible the provision of smallportable air compressors adapted for use in garages, dentists officesand many other situations where a small portable compressor is needed.The smallness and portability of the machine are enhanced by reason ofthe fact that no storage tank ,is required, as the chamber 24 serves todamp the pulsations due to the successive discharges from the cylindersand thus substantially equalize the pressure of the air flowing from thepipe 40.

The substantially uniform pressure of the air discharged from the pipe40 is due in part to the use of. five cylinders, the largest number thatcan be provided without interference of the levers 41 with one anotherin the operation of the machine.

The compactness and hence portability of the machine are furtherpromoted by the use of a cam to actuate the pistons of a set ofcylinders, the cylinders being all in the same plane. A series of cranksarranged along a shaft would require more room, and would necessitatethe distribution of the cylinders into a plurality of planes.

The relatively large chamber l! in constant 1 communication with theatmosphere permits air to flow freely to the cylinders on the successiveintake strokes of the pistons.

The use of a single intake pipe, as 3?, permits of the use of a singleair filter (not shown) for all of the cylinders.

I claim:

1. A rotary compressor or the like which comprises a stationary shaft, acasing rotatably mounted thereon, said casing being formed withgenerally radial projections, compression cylinders mounted on saidprojections with the longitudinal axes of the cylinders positionedsubstantially tangential to the path of movement of the cylinders aboutthe shaft, pistons in the cylinders, a stationary circular cameccentrically mounted on the shaft inside of the casing, a lever foreach cylinder pivoted in the casing, rolls on one end of said leversengaging said cam to impart a rocking motion to the levers as the casingis rotated, and links connecting the opposite ends of said levers to thepistons in the respective cylinders, inlet and outlet chambers formed inthe casing, pipes connecting the chambers with the cylinders, oppositelyacting check valves respectively positioned in the pipes, and meansextending lengthwise of the shaft for affording constant communicationwith said chambers during rotation of the casing, said cylinders beingsecured at their bases only to the said projecting portions of thecasing to provide free passage of air against the head and along allsides of each cylinder when the casing is rotated.

2. An air compressor or vacuum pump having, in combination, a stationarysupporting shaft; a casing rotatably mounted on and wholly supported bysaid shaft, said casing comprising a mechanism chamber having a seriesof peripheral projections, each projection providing ,a seat; a seriesof cylinders, each having a base secured to one of said seats, saidcylinders being arranged substantially tangentially of and upon theperiphery of the casing, each cylinder having a head; air intake and airdischarge means for the head of each cylinder; means for rotating thecasing on the axis of. the shaft in the direction to revolve thecylinders head-first and thus produce a flow of cooling air against thecylinder heads and along the walls of the cylinders; a piston in eachcylinder; and mechanism within the mechanism chamber for converting therotation of the casing into reciprocatory movement of the pistons, saidchamber being adapted to contain a quantity of oil for lubricating saidmechanism and pistons, the tangential arrangement of the cylinderspreventing centrifugal force from driving the oil into the heads of thecylinders.

3. An air compressor or vacuum pump having, in combination, a stationarysupporting shaft; a casing rotatably mounted on said shaft, said casingcomprising an air inlet chamber, a mechanism chamber and an airdischarge chamber arranged side by side in the order stated; a pluralityof cylinders arranged in a single plane and secured to the outside ofsaid casing in the plane of the mechanism chamber, each cylinder havingan open end communicating with said mechanism chamber; a piston in eachcylinder; means for rotating the casing; means within the mechanismchamber for converting the rotation of the casing into reciprocatorymovement of the pistons; means including check valves connecting theopposite ends of the cylinders to the air inlet chamber; means includingcheck valves connecting the last-mentioned ends of the cylinders to theair discharge chamber; means for admitting air to the inlet chamberadjacent to the axis of the shaft; and means for discharging air fromthe discharge chamber adjacent to the axis of the shaft.

4. A rotary compressor or the like which comprises a stationary shaft, acasing rotatably mounted thereon, said casing being formed withgenerally radial projections, compression cylinders mounted on saidprojections with the longi tudinal axes of the cylinders positionedsubstantially tangential to the path of movement of the cylinders aboutthe shaft, pistons in the cylinders, a stationary circular cameccentrically mounted on the shaft inside of the casing, a lever foreach cylinder pivoted in the casing, rolls on one end of said leversengaging said cam to impart a rocking motion to the levers as the casingis rotated, and links connecting the opposite ends of said levers to thepistons in the respective cylinders, inlet and outlet chambers formed in3 the casing, pipes connecting the chambers with the cylinders,oppositely acting check valves respectively positioned in the pipes, andmeans extending lengthwise of the shaft for affording constantcommunication with said chambers during rotation of the casing, saidcylinders being secured at their bases to the said projecting portionsof the casing to provide free passage of air against the head and alongthe sides of each cylinder when the casing is rotated.

ALBERT H. COLEMAN.

